Guided missile



W. K. ERGEN GUIDED MISSILE June 30, 1959 5 Sheets-Sheet 1 Filed 001:. 9, 1952 William R. Era ETL w. K. ERGEN GUIDED MISSILE June 30, 1959 5 Sheets-Sheet 2 Filed Oct. 9, 1952 grwc/mo o ISQE \Jfl Ham K Er HETI 7644M+Q. V/

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GUIDED MISSILE Filed Oct. 9, 1952 5 Sheets-Sheet 4 INVENTOR. William K Eraen.

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William K. ET'SBT'L United States Patent v 2,892,600 GUIDED MISSILE William K. 'Ergen, Oak Ridge, Tenn., assignor to the United States of America as represented by the Secretary of the Army Application October 9, 1952, Serial No. 313,950

22 Claims. (Cl. 244-14) This invention relates to guided missiles particularly of the self-propelled type wherein the missile is constrained or steered through a generally predetermined path until it is locked upon the target by remote command to its radar.

It is the principal object of this invention to provide a missile of the type mentioned wherein the initial trajectory is vertical to a predetermined altitude, followed by leveling off, a level flight of indeterminate distance and a guided glide downwardly in a path intersecting the target.

Another object is the provision of a gyroscopic control for guiding the missile on its trajectory, in conjunction with auxiliary equipment cooperating with such gyro scopic control to cause the missile to traverse the successive distinct portions of a predetermined trajectory until given over to command of its radar.

More specifically, it is an object of the invention to provide a guided missile wherein the positions of the control vanes or elevons thereof, are determined by gyroscopically-controlled servomotors and wherein changes in attitude of the missile are effected by specific precessioninducing forces applied to the gyroscopes.

It is a tturther object to provide a missile which will rise vertically to a predetermined altitude, automatically level ofi in the general direction of the target, traverse a generally horizontal path under remote control followed by a-downward glide under control of radar homing apparatus.

A still further object is the provision of means cooperating with one of the control gyroscopes whereby the missile may be turned from its vertical path into the horizontal, at a predetermined altitude, without the application of precessing forces to the gyroscope and without change of position of the gyro spin axis relatively to the vertical.

Yet another object is the provision of a missile of the type aforesaid, wherein the generally-horizontal part of its trajectory is made at pre-set constant ambient atmospheric pressure.

Another object is the provision of a guided missile wherein the final glide or dive to the target is under control of a steering mechanism positionally controlled by gyroscopes, in turn controlled by radar.

A still further object is the provision of a guided missile wherein steering during initial portions of the trajectory is controlledby gyroscopes while the final phase is controlled by mechanism precessing the gyroscopes under control signals from the radar.

One object of the invention is the provision of a homing radar-controlled missile wherein the smoothing time, that is, the time between an indicated change in heading or pitch from the radar, and the angular response of the missile under control of its vanes, or wings, varies in accordance with the range or target distance, whereby the smoothing time'will be large for large target distances, and shorter for'close ranges to the target.

2,892,600 Patented June 30, 1959 Another object is the provision of a guided missile having control vanes, fins or elevons, servomotors for operating the vanes, a pair of neutral gyroscopes controlling the vanes, means precessing the gyroscopes in response to desired changes in course or altitude of the craft, and means including a radar for successively controlling and energizing the gyro-precessing means whereby the missile is caused to traverse the desired trajectory previously described.

Other objects and advantages will be obvious or become apparent after a study of the following description in connection with the accompanying drawing wherein:

In the drawings:

Fig. 1 is a diagrammatic view of the electrical circuits and mechanical controls by which the missile is guided in a path of predetermined configuration terminating at the target.

Fig. 2 is a view showing the critical portions of the missiles path and the relative positions of the control gyros at the indicated points along the trajectory of the missile.

Fig. 3 is a detail view showing schematically the connection between one of the servomotors and its vane or elevon.

Fig. 4 is an elevation, partly in section, of the yaw and roll gyroscope together with its control potentiometers and precessing motor.

Fig. 5 is a plan view of the pitch gyroscope and its control potentiometer.

Fig. 6 is an elevation of the pitch gyroscope, showing in greater detail the control potentiometer and the motor for rotating the same to efiect a change in trajectory of the missile.

Fig. 7 is a detail sectional view on line 7-7, Fig. 6 showing to an enlarged scale the potentiometer winding and supporting sector.

Fig. 8 is a detail schematic view of the mechanism for producing a potential proportional to air-speed.

Fig. 9 is a detail view of one possible form of mechanism for varying the adjustment of a potentiometer slider in accordance with absolute ambient air pressure.

Fig. 10 is a diagram of the distances and angles involved when the missile traverses a curved path.

Fig. 11 is adiagram of a smoothing circuit embodied in the invention.

Fig. 12 is a plan view of a control switch actuated at the command to lock on the target whereby the missile is first turned into the. missile-target line and then guided along said line.

Fig. 13 is a section on line 1313, Fig. 12.

Fig. 14 is a plan view, partly in section, taken along line 1414, Fig. 13.

Fig. 15 is a plan view of one of the special switches used in the control circuits. 7

Fig. 16 is a plan view of another special switch used in the control circuits.

Fig. 17 is a diagram showing the angular relation between the target-missile line, the longitudinal axis of the missile, and the trajectory or actual path of travel of the missile, and

Fig. 18 is a diagram showing a radar antenna positioning system.

Referring in detail to the drawings, the numerals 1 through 4 indicate the vanes or control surfaces of the missile, the latter being generally identified by the numeral 6. It will be understood that these vanes are hinged to the missile casing or frame for pivotal movement about respective axes, each axis being normal to the longitudinal axis of the missile in the plane of its vane. Referring to the path of the missile during its horizontal flight, vanes 1 and 2 control the pitch or angular movement in the vertical plane through the path, while vanes 3 and 4 control yaw or angular movement in the horizontal plane through the path. In a manner hereinafter explained, all vanes may be simultaneously pivoted in the same sense to control roll, that is, angular movement about the longitudinal axis of the missile. Vanes 1 and 2 are located upon diametrically opposite sides of the missile and preferably rotate about the same line 7, Figure 3. Likewise vanes 3 and 4 are located upon diametrically opposite sides of the missile and preferably rotate about the same line which is perpendicular to 7. These two lines may lie in a common plane normal to the central longitudinal axis 5 of the missile. All vanes may be of the balanced type shown.

The pivotal positions of the vanes 1 to 4, are controlled by respective servomotors 9 to 12 mounted on the casing of the missile. Figure 3, shows an alternative form which the control may take wherein vane 2 is shown in dotted lines. A shaft 13 is fixed to the vane coincident with its axis 7 which axis is normal to the plane of the paper. The shaft is journaled in suitable bearing means, not shown, carried by the casing of the missile, and extends into the casing where it has an arm 14 fixed radially thereto. This arm has a slotted end 14a in which engages a crank 15 fixed to, or positively driven by, the shaft of servomotor 10. A like connection may be provided between each of the other servomotors 9, 11 and 12 and its respective vane.

All of the servomotors are reversible and each is energized through a respective amplifier 16, 17, 18 and 19. For example, these motors may be shaded pole machines identical in construction and power whose direction of rotation is controlled by the phase of the output of the respective amplifiers. It will be understood that each crank such as 15 may be driven from its motor through conventional reduction gearing.

The voltage input to each amplifier is under the control of respective potentiometer networks. One potentiometer is under control of a gyroscope in a manner subsequently explained, while another potentiometer is actuated or adjusted by the corresponding servomotor. The connections are such that pivotal movement of a gyroscope relatively to the missile, in one direction or the other, effects a corresponding adjustment of one potentiometer to unbalance the network, energize the amplifier and cause rotation of the servomotor and its vane in a corresponding direction. By a follow-up connection, rotation of the servomotor effects adjustment of another potentiometer of the network to again balance the network, restore the amplifier input to zero and stop the motor. The resulting angular movement of the vane then effects a corrective movement of the missile relatively to the gyroscope until the initial relation is restored. The action is smooth and the response substantially instantaneous so that the missile is at all times under the control of the gyroscopes and the precessioninducing coils thereof.

For example, amplifier 16 is under control of a network including a control potentiometer 20 and a followup potentiometer 22. Slider 21 of potentiometer 20 is actuated and controlled by a gyroscope as subsequently explained. A secondary 28a of a transformer is connected across the terminals of the potentiometers and acts as a source of AC. voltage. In this way, a shift of the slider 21 in response to relative angular movement between the gyroscope and the missile about the longitudinal axis of the latter, causes a voltage to be applied to the amplifier. The phases of the voltage and hence the resulting direction of rotation of follow-up or servomotor 9 will depend upon the direction of movement of the slider. The resulting movement of motor 9 effects both an angular adjustment of its elevon or vane 1 (which tends to correct or annul the initiating relative angular movement between the missile and gyroscope) and simultaneously adjusts slider 23 through mechanical connection 24 in a direction tending to annul the voltage applied to the amplifier. The action is smooth and the response substantially instantaneous. For each deviation or roll, the corrective action continues until the parts have been restored to the initial position wheerin the missile is in correct angular position about its longitudinal axis with respect to the gyroscope, that is, wherein the initiating roll is annulled.

Servomotors 10, 11 and 12, each controlling its respective vane or elevon 2, 3 and 4 are similarly controlled so that it is sufficient to identify amplifier 17, control potentiometer 25 and its slider 26, follow-up connection potentiometer 27 and its slider 28, secondary 29, and mechanical follow-up connection 13, all for control of motor 10. Similarly, motor 11 is under control of amplifier 18, potentiometer 30 whose slider 31 is under gyroscopic control, second or follow-up potentiometer 32 having slider 33 actuated by mechanical drive 34 from the motor, and a secondary 35. The drive 34, of course, also extends to fin or elevon 3.

Servomotor 12 is similarly controlled by amplifier 19, potientiometer 36 and its gyro-controlled slider 37, second potentiometer 38 and its slider 39, secondary 40 and mechanical follow-up connection 41 extending from motor 12 to slider 39 and control vane or elevon 4.

It will be noted that potentiometer 20 is connected with its follow-up potentiometer 22 in a reverse sense, as indicated by the crossed connectors. Thereby the vanes 1 and 2 are pivoted in opposite directions for a roll movement of the gyroscope relatively to the missile. A like function is effected by the reversed connections of the controls for vanes 3 and 4. Thus, for example, for an incipient clockwise roll of the missile looking from the rear thereof, vane 1 is pivoted downwardly, vane 2 upwardly, vane 3 is pivoted to the right and vane 4 to the left, until the incipient roll is annulled and normal relation of the roll gyroscope and missile is restored.

The major axes of control are (l) the longitudinal or roll axis of the missile, (2) the normally vertical or yaw axis, and (3) the normally horizontal transverse or pitch axis. While, theoretically, it is possible to use three gyroscopes, each controlling angular movement about a respective one of the identified axes, it is contemplated that, in the interest of simplicity and economy, one gyroscope will control angular movement in roll and yaw (axes 1 and 2) while a second gyroscope will control angular movement in pitch (axis 3).

Both gyroscopes are of the type known as neutral, three-degree-of-freedom instruments wherein an electrically, or pneumatically spun rotor is mounted in a first or inner gimbal, which gimbal is mounted in a second or outer gimbal for pivotal movement about a second axis which is normally perpendicular to the spin axis of the rotor. The second gimbal is then mounted for pivotal movement in its frame or support for angular movement about a third axis normally perpendicular to the aforesaid second axis and to the rotor spin axis. The first axis or degree of freedom is, of course, the rotor spin axis. All three axes are concurrent at a point coinciding with the center of gravity of the first gimbal and stator and rotor parts carried thereby. The outer ring is balanced about its axis so that the gyroscopes are substantially unaffected by external ballistic forces otherwise caused by changes in velocity or angular movements. Any suitable known erecting mechanism may be provided for the gyroscopes. For simplicity and clarity of illustration and description, three gyroscopes have been shown upon Fig. 1, while the preferred construction of the two gyroscopes is shown upon Figs. 4, 5 and 6.

Referring to Fig. 1, the roll gyroscope is identified by the numeral 42 and the yaw gyroscope by the numeral 42', to indicate the identity or relation between them. The mechanical connection between gyroscope 42 and the four potentiometer sliders 21, 26, 31 and 37 is indicated at 43 which in Fig. 4 is typified by a trunnion of the gyroscope. Fig. 4 shows the gyroscope in greater detail. In this figure, indicates the longitudinal axis of the missile and 44 a portion of the framework of the missile. A bracket 45 is secured to framework 44 as by bolts 46 and has arms 451; with aligned bores or bearings defining the pivot axis 5' of the outer gimbal 47 which has aligned trunnions 48 and 43 journaled in these hearings, whereby the gimbal and all parts supported thereby may pivot about the longitudinal axis of the missile. Ring 47 has bearings 47a and 47b defining an axis 50 at right angles to the axis of n'unnions 48 and 43. The inner gimbal 51 has aligned trunnions 52 and 53 journaled in respective bearings 47a and 47b and supports diametrically opposite, aligned bearings one of which is identified at 54 and which support the rotor 55 for spinning about an axis 56 normal to the plane of the figure and at right angles to axis 50. The latter axis is therefore at all times at right angles to the longitudinal axis of the missile. It will be understood that rotor 55 may be continuously spun at high speed by any suitable known electrical or pneumatic means wh1ch have been omitted to avoid unnecessary complication of the drawing. Also suitable known, releasable centralizing and locking means, not shown, may be provided to locate and secure the rings in predetermined positions such as those shown upon the figure, prior to launching of the missile.

Because of the inertia of the spinning rotor, any roll of the missile will result in relative angular movement of ring or gimbal 47 relatively to bracket 45.

Trunnion 43 extends a distance beyond arm 45a and has the potentiometer sliders 21, 26, 31 and 37 fixed thereon. As shown, these sliders are electrically insulated from the trunnion and from each other and each comprises an arm radial of axis 5' and extending into sliding contact with its potentiometer winding. These windings 20, 25, 30 and 36 are shown mounted upon or carried by a bracket 57 attached to lower arm 45a and are, of course, arcuate about axis 5' so that the sliders are in contact with their respective windings over the entire range of angular movement of ring 47 about axis 5. It is contemplated that this range will be only a few degrees in each direction from neutral so that the leads from the sliders 21 etc. may be soldered or otherwise secured directly thereto, as shown.

The voltages impressed upon potentiometers 30 and 36 are varied by a potentiometer 58 and its slider 59 in accordance with any yaw of the craft. When the missile is on the horizontal portion of its path, yaw has the usual meaning of angular deviation from the desired trajectory in a horizontal plane through the longitudinal axis of the missile. When the missile is on the vertical or initial portion of its trajectory, yaw will be angular deviation in a plane through the longitudinal axis, normal to the plane of Fig. 2. Since axis 5' is fixed parallel to such longitudinal axis, yaw will be detected by an angular movement of gimbal ring 51 relatively to ring 47. Accordingly, I propose to mount potentiometer 58 upon a bracket 60 secured to ring 47 in a position concentric with axis 50, and to fix slider 59 to the outwardly-extending end of trunnion 52, as will be obvious from inspection of Fig. 4. From Fig. 1 it will be noted that slider 59 is electrically connected with sliders 31 and 37. The mechanical connection between the gyroscope 42' and slider 59, is indicated at 52 and in the detail view of Fig. 4 is a trunnion of ring 51. Hence any yawing, that is, angular movement into or out of the plane of Fig. 2, correspondingly applies a voltage to amplifiers 18 and 19 and causes servomotors 11 and 12 to operate. The hook-up is such that servomotors turn in the same direction and pivot vertical fins 3 and 4 in the same direction, thereby effecting a corrective yaw of the missile. The correcting action continues until the deflection has been annuled and the trajectory of the missile is again in the vertical target-missile plane as determined by the gyroscope. A counterweight 61 may be mounted on ring 47, for limited movement therealong, to balance the weight of bracket 60 and parts carried thereby, about axis 5'. For the purpose of applying a torque to the gyroscope inducing precession about axis 50, I have provided a well-known reversible torque motor 62 having its casing fixed to arm 45a and its rotor directly coupled to trunnion 48. When properly energized in a manner to be explained, this motor acts to apply a torque to ring 47, in one direction or the other and thereby induces a corresponding precession or angular movement of the gyro rotor and ring 51, about axis 50 whereby slider 59 is correspondingly adjusted over potentiometer winding 58. The relation between the direction of the torque applied by motor 62 and the resulting direction of precession about axis 50 will, of course, depend upon the direction of spin of the rotor 55. The manner and means by which potentiometer winding 58 is energized, will be hereinafter explained. Suflice it to say that when a change in heading is indicated, a voltage of proper phase is applied to motor 62 and results in a torque on ring 47 in a corresponding direction about axis 5'. The gyroscope then precesses in the proper or desired direction and in so doing adjusts slider 59 and effects operation of servomotors 3 and 4 in the same direction. The action is smooth and continues until the indicated change of heading has been efiected whereupon motor 62 is deenergized and precession ceases.

Pitch of the missile is defined as the angular movement thereof from the desired trajectory in the vertical targetmissile plane, which for purposes of present description, may be taken as the plane of Fig. 2. This angular movement is detected by a pitch gyroscope generally identified by the numeral 63. This gyroscope is of the same general type as gyroscope 42. That is, it is a neutral, threedegree-of-freedom instrument. However, the axes are differently disposed with respect to the missile and since it is used to detect pitch only, it controls but a single potentiometer. There are other minor differences, principally in the movable mounting of the potentiometer winding. 1These differences will be subsequently explained in detai Gyroscope 63 is shown in detail in Figs. 5 and 6 and comprises a base or bracket 64 having upstanding arms 64a and 64b which have bearing means at their upper ends defining an axis 65. An outer gimbal or ring 66 has trunnions 67 and 68 journaled in these hearings for pivotal movement about axis 65, which axis is perpendicular to the longitudinal axis of the missile casing.

In the construction shown, the axis of the pitch gyroscope 63 lies in the plane of maneuver, that is the vertical target-missile plane and may be conveniently initially positioned vertically. The gyroscope is thus not affected by rolling of the missile, that is, movement about its longitudinal axis, during vertical ascent.

Trunnion 68 projects a substantial distance beyond arm 6411, as is clear from Fig. 5, and has a potentiometer slider 75 fixed thereto. A worm sector 76 has a hub 76a journaled upon a reduced concentric sleeve fixed with the arm 64a and spokes or arms 76b mounting the sector coaxially with axis 65. The sector is generally channel shaped in cross section as shown in Fig. 7, and carries a potentiometer or winding 77 wound upon a form 78 and fixed within the channel by means of an insulating form 79 in position for engagement by slider 75 for all positions of the slider over the winding. The total angular extent of the sector and its winding should be a little over say 200. A portion of the sector is broken away in Fig. 6.

Slider 75 and potentiometer 77 appear in Fig. 1 and from this figure, it will be noted that the slider is electrically connected with both of sliders 21 and 26 whereby the input voltages to amplifiers 16 and 17 is, in the one case, the algebraic sum of the voltage variations of potentiometers 20 and 77 and in the other case, the algebraic sum of the variations of 25 and 77. Potentiometer 77 is connected in series with winding 80 which is connected by a central tap with a switch 81. When the switch is connected with its contact 81a the control network to motors 9 and 10 is under joint radar-gyroscopic control as subsequently described. When switch 81 is thrown to grouned contact 81b, the dotted line position, motors 9 and 10 are under gyroscopic control only, as will be obvious from inspection.

On Fig. 1, the mechanical connection between pitch gyroscope 63 and slider 75, is identified by numeral 68 which is a trunnion of ring 66 in Fig. 5. Hence, assuming that the missile, in horizontal flight, for example, undergoes a pitching motion only, that is without yaw or roll so that sliders 21 and 26 remain at rest, the resulting actuation of slider 75 energizes both amplifiers 16 and 17 and causes movement of servomotors 9 and 10 to pivot vanes 1 and 2 in the same direction. The connections, of course, are so chosen, that the resulting movement of the vanes annuls the pitch and restores the missile to horizontal motion.

The missile selected for illustration is intended for vertical launching to a generally pre-determined altitude, followed by a 90 turn into the horizontal and thence into a glide in the general direction of the target. The relation of the gyro axes to the longitudinal axis of the missile during the vertical ascent is indicated in the corresponding portion of the trajectory shown upon Fig. 2 wherein it will be noted that gyroscope 42 has its spin axis normal to the vertical target-missile plane, that is, the plane of the figure. Hence the angular motion of the missile from a vertical to a horizontal path in said plane has no effect upon gyroscope 42 since the axis of angular motion is substantially parallel with the spin axis of this gyroscope.

During the vertical ascent, the pitch gyroscope 63 has its spin axis parallel with the longitudinal axis of the missile and the axis of its outer ring 66 normal to the plane of Figs. 2 and 6. Hence the attitude of the missile in this plane at this time is controlled by the position of slider 75 relatively to winding 77 and the turn from vertical to horizontal flight can be initiated and controlled by pivotal movement of the potentiometer 77. This movement is effected by a motor 82, Figs. and 6, which may be mounted upon bracket 64. A driving connection between the motor and sector 76 is generally identified in Fig. lby the numeral 87 and is shown in the form of a worm 83, Fig. 6, journaled on standard 64a and in mesh with the sector, and bevel gears 84 connected respectively with shaft 85 and the motor. A speed-reducing mechanism and switch 86 may be inserted in this drive to effect the turn into the horizontal at the desired rate. Motor 82 may be a small shaded-pole machine of known construction.

According to the desired flight path of the missile, it is necessary that the missile be at a predetermined altitude, say about 35,000 feet, and then turned 90 into a horizontal path in the general direction of the target. For this purpose there is provided a pressure-responsive switch 88 including an aneroid element, not shown, of known construction, operable to close contacts at a preselected reduced atmospheric pressure corresponding to a known altitude. The effective absolute pressure at which switch 88 will close its contacts may be selected in a known manner by a set 89 (Fig. 6) having a pointer 90 movable over a scale, not shown, graduated directly in terms of altitude. In order to limit and determine the turn to substantially 90, the motor circuit includes a pair of normally-closed contacts 86a, not shown in Fig. 6, embodied in speed reducer 86. One of these contacts may be an arcuate strip rotated or driven by the reducer and engaged by a spring contact finger. The relation of the parts in such that the arcuate strip moves out of contact with the finger at the instant that motor 82 has rotated a number of turns corresponding to a rotation of winding 77. The control circuit may be traced on Fig. 6 from power lead 91 to pressure-responsive switch 88, lead 92, the aforesaid contacts 86a, lead 93 to motor 82 and thence to ground at 95. Consequently, when missile reaches the altitude set at 89, switch 88 closes and motor 82 rotates to thereby rotate winding 77. In a manner previously described, this causes operation of servomotors 9 and 10 to thereby pivot vanes 1 and 2 and turn the missile in the desired direction toward the horizontal. The action may be smooth and continuous. That is, by proper coordination of the rates of response of the servomotors, the rate of turn of the missile and the speed of turning of winding 77, the deflection of slider 75 from null voltage position may remain substantially constant until the turn has been completed and the circuit of motor 82 has been opened by separation of the contacts 86a. The spin axis of gyro 63 remains vertical during this operation as will be clear from Fig. 2. Hence under such conditions the active or rotatable portion of winding 77 may have only a few degrees of angular extent although, of course, it may extend through a much larger angle, as shown in Fig. 6. It is also contemplated that this winding may be non-linear to apply a voltage increasing at an increased rate with equal increments of rotation from central or null position. It will be understood that the general direction of the target is known and that the missile is oriented before launching until axis 69 is in said general direction. This, however, is not absolutely necessary.

After the missile has turned into a substantially horizontal path, it is under command of the radio link with the shore or launching station. During this portion of its trajectory the direction of travel of the missile in the horizontal plane through the trajectory is controlled by radio signals which result in the energization, in one direction or the other, of torque or precession motor 62.

A radio-controlled relay, not shown, is used to operate a three-position switch 97, shown schematically upon Fig. 1, whereby the phase of a voltage induced in secondary transformer winding 98 may be reversed. Thus, the switch arm may be moved, by means well known in the radio art to any one of the three positions shown, in response to radio signals of three different frequencies. In response to one frequency the switch arm is moved to its uppermost position wherein the induced voltage is applied to motor 62 by lead 99, switch 100, having its arm now in contact with terminal a, and lead 101. This action causes the motor to be energized to apply a torque tending to rotate ring 47 about axis 5 in one direction, say clockwise, looking from the right of Figure 4. For the direction of spin of rotor 55 indicated in this figure, the gyro will then precess counterclockwise about the axis of trunnions 52-53, looking down, and correspondingly turn potentiometer arm 59 to move vanes 3 and 4 in one direction and correspondingly change the direction of travel, or heading, of the missile in the aforesaid horizontal plane. In response to a signal of different predetermined frequency the switch 97 is moved to third or lowest position and the voltage from 98 is applied by lead 99 in a phase opposite to the phase of the previous case. This turns the missile in the horizontal plane in the direction opposite to the one of the previous case. A radio signal of a third predetermined frequency turns switch 97 into its central position and motor 62 is deenergized to stop precession. As such radio controls are well known and, per se, form no part of my invention, this feature has not been described in detail.

During the substantially horizontal flight path or section of the trajectory under discussion, it is also desirable to keep the missile at an altitude such that the air pressure will remain constant. The reason for this is that the motor of the missile operates most efliciently at a given ambient air pressure and therefore this pressure should be kept constant even if it involves some change in altitude. To attain this function, I propose to energize torque motor 96 in response to changes in ambient atmospheric pressure. This may be accomplished by a network shown in Figure 1, including a potentiometer winding 108a having a slider 108a mechanically connected with and operated by an aneroid element 160 responsive to the ambient atmospheric pressure. A lead 159 connects switch terminal 103c and slider 1080. The circuit includes the winding 108 of a second potentiometer having a manually settable slider 106. Voltage is supplied by the secondary 10812. The switch 103 has an arm electrically connected with motor 96.and movable automatically in a manner hereinafter described, to any One of three contacts one of which is 1030. As indicated, lead 159 extends through switch 86b driven by the same mechanism as 86a thereby providing that the circuit cannot be closed until after the missile has reached the appropriate or desired altitude and has traversed the 90 turn into the horizontal. In operation of this feature, slider 106 will be set for a selected altitude before the missile is launched, which altitude, of course, will be somewhat greater than that set into switch 88. Alternatively, slider 106 may be mechanically connected with set 89 in such a manner that the two altitudes may be set simultaneously albeit with a difierence equal to the radius of the turn. Therefore as long as the arm of switch 103 remains on contact 1030, the value of the voltage effective upon precessing or torque motor 96 will depend upon the setting of slider 106. Any change in altitude or change in ambient atmospheric pressure will effect an adjustment of slider 108e, unbalance the circuit, and cause the application of a voltage to motor 96 varying in phase and amplitude with the direction and amount of displacement, respectively, from the neutral position. This position, of course, will be determined by the setting of slider 106. When the missile reaches the altitude corresponding to the setting of slider 106, the circuit is again balanced and no voltage is applied to motor 96. Consequently the gyroscope 63 ceases precession and the missile levels off. With the electrical connections properly related to the direction of spin of rotor 73, the gyroscope precesses about axis 65 in response to the torque applied by the motor, in one direction or the other, depending upon the direction of the applied torque. The resulting precession moves slider 75 over winding 77 and, in the manner previously explained, causes pivoting of vanes 1 and 2 until the altitude has been changed to that corresponding to the preset ambient atmospheric pressure. Thus, when the ambient pressure rises for instance in correspondence with a decrease in altitude the vanes are pivoted downwardly thus causing the missile to climb until it attains an altitude corresponding to the set pressure. Likewise a drop in ambient atmospheric pressure causes the vanes to tilt upwardly and thereby cause the missile to decrease its altitude. In both cases, as soon as the set altitude has been attained, the voltages established by potentiometers 108 and 108a are balanced, motor 96 is de-energized, precession of gyro 63 ceases and horizontal flight is resumed.

In Fig. 9 there is shown an aneroid element generally identified by the numeral 160, for adjusting the slider 108s of winding 108a. Thus, a box 161 has one side closed by a diaphragm 162 to provide an evacuated chamber. A nut 163 has a central bore to accommodate a shaft 164 with smooth sliding fit. The wall of the bore has a helical slot of large pitch and a pin or stud 165 fixed to shaft 164 rides in and along the slot. The shaft is fixed with diaphragm 162. Nut 163 is journaled in a bracket 166. By this construction, changes in ambient air pressure cause flexing of diaphragm 162 and the re sulting reciprocation of shaft 164 effects a turning of nut 163 and potentiometer slider 108e, aifixed thereto. The winding 108a is conveniently mounted within an insulating form 167 carried within an arcuate channel member 168 fixedly carried by bracket 166.

It is not necessary to provide any means for causing precession of gyroscope 42 about its roll axis 5. This gyro will maintain its spin axis fixed for the comparatively short time of flight of the missile. Furthermore, a slight roll in one direction or the other will not be particularly objectionable. For example, with a slight roll or deviation of the pivot axes of vanes 1 and 2 from horizontal, a command signal to turn right or left would also result in a slight change of altitude which would be at once compensated or corrected by the aforesaid altitude control. Likewise, an up or down command from the pressure-responsive control will result in a slight change of heading which can be corrected by lateral control signals.

At the end of the horizontal flight, as just described, at a point determined from the control or launching station, the gyros are caused to precess from their positions shown adjacent the horizontal flight path of Fig. 2, to positions determined by the direction of the missile-target line. Gyro 63 will be precessed by mechanism subsequently described, energizing torque motor 96, into a direction perpendicular to the missile-target line. The spin axis of gyro 63 is therefore in the vertical target-missile plane. Gyro 42 is precessed right or left by an appropriate signal applied to torque motor 62, to correspondingly effect precession about axis 50 and thereby adjust slider 59 of potentiometer 58. Since the missile makes its turns from horizontal flight to dive substantially about the spin axis of gyro 42, the latter is not affected by such turns.

The homing apparatus is given command of the missile in response to a signal from the shore or command station, to effect a turn into the general target-missile line and to thereafter control the final glide to the target. The apparatus includes a radar mechanism of known type and construction, including a universally mounted dish or parabolic reflector identified at 109, Fig. 1. As is well understood in the art, this dish is continuously rotated about an axis making a small scanning angle with the axis of the generating parabola. The dish is also mounted for adjustment about two mutually normal angles, namely, a normally horizontal axis at right angles to the aforesaid axis of rotation, and a normally vertical axis perpendicular to the aforesaid horizontal axis. Follow-up motors, not shown, are provided to effect angular movement about the respective axes in response to echo signals which, when reflected from the target, are detected, amplified and used to control the motors to maintain the dish directed thereon except for scanning motion. As such mechanism is well known and, per se, forms no part of the present invention, it is sufficient to refer to the patent to Earl C. Sparks and Moulton B. Taylor, 2,512,693, granted June 27, 1950 as showing a suitable radar control of the type just mentioned. See also Patent 2,459,117, granted January 11, 1949 to B. M. Oliver. It will be understood from the foregoing, that shaft is driven by movement of the servomotor (not shown) controlling or rotating the radar dish about its vertical axis, while shaft 111 is driven in elevation by a servomotor (not shown) controlling or rotating the radar dish about a normally horizontal axis.

The geometry of the turn from the horizontal into the glide or dive upon the target is shown in Figure 10. It is evident that e is the azimuth and e the depression of the target as viewed from the horizontally flying missile. These angles are memorized in the differentials 113 and 121 inasmuch as the clutches 112 and are closed or engaged when the command to lock in on the target is given. At all other times these clutches are disengaged; and they disengage again as soon as the angles are memorized in the differentials. The mechanism by which the foregoing functions are effected will be subsequently described in detail.

As soon as the radio command is given, turning the missile over to control of the radar, the axis of dish 109 is automatically directed upon the target. The resulting motion of shaft 110 is transmitted to differential 113 through clutch 112. The same signal or command effects closure of clutch 114 which connects two aligned portions of shaft 115. As indicated upon Figure 1, this shaft is connected with one side of differential 113 and extends to precessing or torque motor 62 thereby indicating that as soon as switch 100, controlling precession of torque motor 62 is moved to make the proper contact, shaft 115 drives one side of difierential 113 at a rate proportional to the rate of precession of the gyroscope. Actually, it is contemplated that shaft 115 may be driven by a small fractional horsepower motor (not shown) energized by the same or a proportional voltage as that used to energize torque motor 62. In this way, the speed of the driving motor and hence of shaft 115 will be proportional to the rate of precession of the gyroscope 42 since the voltages applied to the driving and precessing motors will always be constant and bear a predetermined relation.

From Fig. 1, it is noted that the third side of differential 113 is connected by shaft 116 with switch 100 and also with a switch 117. The connections are such that, as soon as shaft 110 is actuated as the radar locks upon the target, shaft 115 being at this time motionless, shaft 116 is thereby operated to shift the arm of switch 100 to contact or 1000, depending upon the azimuthal direction of the target, right or left, at the instant the command is given. Shaft 116 also moves the arm of switch 117, in the manner shown upon Figs. 12, 13 and 14, as and for the purpose hereinafter described in detail. Upon contact of the arm of switch 100 with terminal 10% or 100:: motor 62 is energized to apply a precessing torque, in one direction or the other, to gyro 42 and thereby pivot vanes 3 and 4 in the proper direction. The torque motor is energized in the proper phase by the secondary 122 having a grounded center tap and its terminals connected with contacts 10% and 1000, respectively. Therefore the direction of torque and resulting precession will depend upon the direction of movement of the arm of switch 100. Fig. 12 shows the preferred arrangement or succession of contacts. The arrangement shown upon Fig. 1 is in the interest of simplicity of the wiring diagram.

As the missile swings into the vertical plane of the target-missile line, the radar retains its axis directed upon the target and, in so doing, shaft 115 is returned toward, and arrives at, its original position. The results of this return movement will be explained in the subsequent description of the final dive upon the target.

Referring to Figs. 12, 13 and 14, it will be noted that shaft 116 has the arms of switches 100 and 117 fixed radially thereto and insulated therefrom as by bushings 116a and 116b. A sector-shaped plate 127 of insulating material is fixed in any suitable manner to the frame of the missile and is interposed between the two switch arms. On one side, plate 127 carries first or outer contact 100a (see also Fig. 1) fixed thereto. This contact is notched or grooved to receive the depending end of a contact element 128 which is mounted for limited radial sliding movement on and along arm 100. The element is urged radially inwardly by spring 129. Due to the complementary shape of the contacting parts 100a and 128, as shown upon Fig. 14, and the action of spring 129, the contacts are yieldingly held together until positively moved apart by turning of shaft 116.

An arcuate contact wall is fixed to plate 127 radially inwardly of outer contact 100a and consists of a central contact 100d of about the same size as contact 100a with contact strips 10% and 1000 on opposite sides thereof. The three contacts are insulated each from the others and the arrangement is such that, depending upon the direction of angular movement of the switch arm, slide 128 will move into contact with strap 10% or 100:: as soon as the slide has cleared contact 100a. The two segments or strips are of sufficient angular extent to accommodate the greatest azimuthal rotation of the radar dish to be encountered in actual use. As the missile is turned in azimuth in response to action initiated by the pivotal movement of the radar dish, the arm of switch is gradually moved toward its initial central position and finally contacts 100d whereby the missile is under complete control of the radar for the final dive or glide on the target, as will be subsequently explained. As indicated upon Fig. 14, contact 100d has a depression therein which, together with the complementary shape of slide 128 and spring 129, yieldingly retains the switch arm in central position once it has moved thereto. In this manner yaw of the missile is controlled solely by the gyroscope 42 during the vertical ascent and the turn into the horizontal, and by the command station through radio control of switch 97 and the gyroscope during the horizontal portion of the trajectory. Up to this point, switch arm 100 continuously engages contact 100a. When the command to lock on the target is given, switch arm is moved by the mechanical connection with the radar dish, into engagement with arcuate contact 100b or 1000, depending upon the azimuthal direction of the target, to effect the necessary change of heading concurrently with the initiation of a downward glide and, finally, when the necessary change in heading in azimuth has been completed, control is solely by the radar. It is to be noted however, that control in azimuth at all times, is effected by precession induced in gyroscope 42 by torque motor 62, albeit by different agencies.

Switch 117 which is also mechanically connected with shaft 116 may be of the same general construction as switch 100 so that it is sufficient, referring to Fig. 13, merely to identify slide 130, spring 131 and contacts 117a and 117b. However, the several contacts are differently electrically connected as indicated upon Fig. 15 where it will be noted that the radially outward central contact, as well as the arcuate contacts, are all interconnected. It is for this reason that all three are identified by the reference character 117a upon Fig. 15. Consequently, contact is maintained at 117a until the switch arm has been fully restored to central position, at which time contact is made at 117b only, to thereby place the missile under control of the radar.

It has been explained that the shaft 125 is connected with switches 81 and 103 to actuate the same as the radar dish pivots downwardly at the command to look upon the target. Although switch 103 requires only one arcuate contact strip 103b, due to the fact that the missile turns downwardly only, for practical reasons, it may be desirable to make all switches of the same construction and switch 103 has been so shown upon Fig. 16.

Initially, that is, up to the time the command to lock in on the target is given, the arm of switch 103 makes contact at 1030. As the arm is rotated by shaft 125 the slider thereof moves radially into contact with contact 10317 and remains there until, as the arm is restored to the central position, it engages contact 103a. Hence contact is made at 103!) during the time the missile is turning downwardly into the final glide to the target and shifts to 103a as the missile moves into the missile-target line.

Switch 81 has the same action as switch 117 and, of course, has its arm mounted upon shaft 125 in the same manner as the arm of switch 117 is mounted upon shaft 116. Contact of switch 81 at 81a and of 117 at 1171; may also be utilized to open the clutches 112, 114, 120 and 124, as by operating a relay which, when energized, opens an operating circuit of the clutches, which may be of a well-known electromagnetic type.

Continuing description of the turn from the horizontal path into the final dive or glide, as soon as the command to lock on the target is given, dish 109 is directed to the target as previously described. Since the target is always below the missile rotation of shaft 111 is in one direction only, in contradistinction to shaft 110 which may rotate in either direction depending upon the azimuth of the target at the time the command is given. Rotation of shaft 111 drives through differential 118, shaft 119 and clutch 120 to differential 121. Of the remaining two sides of differential 121, one side is connected with a shaft 123 having a clutch 124 therein while the third or remaining side of 121 is connected with shaft 125.

As indicated upon Fig. 1, shaft 123 is associated with torque motor 96 of gyro 63 to be driven thereby at a speed proportional to the rate of precession of the gyroscope. The same command which causes the radar to lock upon the target and closes clutches 112 and 114, also closes clutches 120 and 124. In other words, all clutches are closed at one and the same time. Actually, however, as in the case of shaft 115, it is contemplated that shaft 123 may be driven through reduction gearing (not shown), by a separate motor (not shown) connected therewith. Since the energization of the precessing or torque motors is in this case a simple on-otf operation, the energizing voltages applied to the respective torque motors 62 and 96 are constant and, within the relatively small range of precession, the rates of precession are likewise substantially constant. Hence, each of the shafts 115 and 123 may be driven by synchronous motors of small fractional horsepower and by proper proportioning of the reduction drives, will turn their shafts at rates very closely proportional to the respective rates of precession.

As indicated upon Fig. 1, shaft 125 is connected to drive switches 81 and 103. Switch 81 which has, up to this point, been in contact with grounded terminal 81b, maintains such contact during the turn. The arm of switch 103 is moved to contact 10312 to thereby complete the circuit through torque motor 96 and a source of constant voltage represented by secondary 126 so that the gyro 63 is thereby caused to precess clockwise about axis 65, as viewed in Fig. 6, to thereby efiect operation of fins or vanes 1 and 2, as previously described, and cause the missile to turn downwardly to the proper glide angle to the target.

In order to bring the missile to the target, it is advantageous to apply an acceleration which is given by the equation:

Where V is the air speed, c is the angle between the direction in which the missile is going and the line of sight from the missile to the target, and D is the instantaneous range.

In order to obtain this acceleration, an angle of attack is required, where C is a constant for the problem at hand. The attitude of the missile will thus differ by this angle of attack from the actual trajectory or path of travel. In order to compute the required angle of attack, dividing amplifiers are provided. Since the gyroscope 42 is positioned to give the direction in which the craft is going, this direction, if algebraically added to the angle of attack, as computed by one dividing amplifier, gives the direction in which the missile has to be stabilized.

The direction in which the missile is supposed to fly changes at a rate Hence the gyroscope 42 has to be precessed at a rate proportional to V, sin e/D. The voltage for the control of the precession mechanism is obtained from a voltage proportional to sin e/D by feeding the latter into potentiometer 101 and by positioning the slider thereof in accordance with airspeed, V,,, as previously explained. Therefore both the rate motor and the dividing amplifier need a voltage proportional to sin e/D. It is the function of the dividing amplifier, generally identified by numeral 133, to produce such a voltage.

Both the processing motor 62 and the dividing amplifier therefore require a voltage proportional to sin e/D. This voltage is obtained from an angle converter 134 consisting of a fixed coil 135 and a rotatable coil 136, in inductive relation therewith. As such instruments are well known in the art, it is not necessary to describe them in detail. It is sufiicient to explain that the voltage induced in rotatable coil 136 is proportional to the product of the voltage applied to coil 135 and to the sine of the angle between the axes of the two coils. The fixed coil 135 is energized by a circuit including leads 137 and 138, with a voltage proportional to inverse range as by means incorporated in the radar itself or, where the glide angle is substantially constant, by means responsive to ambient air pressure and establishing a voltage inversely proportional to the altitude of the missile over the target. The rotor 136 of converter 134, is positioned in accordance with e which is the algebraic sum of the angle t: between the attitude of the missile, that is, the angular position of its longitudinal axis and the missiletarget line and a, the angle of attack. This summation is effected mechanically by a differential 139 having one side driven from the radar by a shaft 140, in the same manner as shaft 110, and a second side operated by a vane 141 and shaft 142. The vane is pivoted on the missile externally thereof for pivotal movement about a normally vertical axis and responsive to the slip stream. The output of the differential 139 is represented by the angular position of shaft 143 and is transmitted thereby to coil 136 of the angle resolver, and a voltage proportional to sin e/D, is applied by leads 144 and 145 to the dividing amplifier 133, and by lead 146 to potentiometer 147 which, it will be noted, has its slider 148 connected for actuation by the same air speed meter or responsive device 104 that adjusts slider 102 of potentiometer 101. A part 149 such as a link, may connect the sliders 102 and 148, for conjoint adjustment by airspeed meter 104.

Figure 8 shows one form which such meter may take, wherein 6a identifies a forwardly-facing exposed portion of the missile casing. A diaphragm 169 is exposed to the dynamic pressure of the air caused by the forward travel of the missile and is deflected to an extent substantially proportional to air speed over the effective speed range of the missile. This deflection is tranmsitted to a lever 170 by a link connection 171. The lever is pivoted at 172 to a frame 173 secured to the casing 6a and has a pair of oppositely-disposed insulated contacts 174 and 175 adapted to engage contacts 176 and 177, respecti ely, upon frame 173. These contacts control a reversible follow-up motor 178 energized from a power supply 179.

The end of lever 170 remote from link 171 has a slot within which a slide 180 is movable. One end of a spring 181 is connected to this slide. The other end of the spring is attached to a screw 182 mounted for axial translation but fixed against rotation by a squared end 182a fitting a corresponding hole in a part 6b fixed to the rocket casing. A gear 183 is threaded upon this screw and is fixed against axial movement by a yoke 184. The gear meshes with a Worm 185 fixed to shaft 186 of the motor. The connections are such that the rotation of the motor and resulting tensioning of spring 181 oppose the force exerted upon diaphragm 169. Hence for any given speed of the missile, the spring tension necessary to open the motor circuit, is a measure of the air speed. Shaft 186 has a second worm 187 thereon which drives a gear 188 having a potentiometer arm 148 thereon. The arm carries a slider movable over winding 147, so that the angular adjustment of the arm and the potential established by its winding, is proportional to air speed. In order to correct for errors otherwise introduced by variations in air density with altitude,

the slide 180 is adjusted in and along the slot in lever 170 by an aneroid element 191 mounted upon wall 6a and connected with the slide by a bell crank 192, pivoted at 193 on bracket 194. A sliding connection between the adjacent end of the bell crank and slide 180, compensates for the small permissible range of angular movement of the lever 170. In this way, a decrease in atmospheric pressure with increasing altitude increases the effective arm of the lever 170 and compensates for the decrease in air density and the otherwise low value of air speed resulting therefrom.

Figure 17 shows geometrically why and c are algebraically added to give 6. It will be noted, as previously described, that the arm of switch 117 makes contact at 117a until the missile is on the final glide or dive on the target, when contact is made at 117b to connect the dividing amplifier 133 and angle converter 134 into the control circuit of servomotors 11 and 12.

For a like purpose, that is, for controlling the pitch or angle of glide or dive on the target during the final phase, I provide a second dividing amplifier 150 and angle converter 151 each of which may be of similar construction with its counterpart 133 and 134, respectively. The primary coil 152 of angle converter 151 is connected in parallel with primary 135 of angle converter 134. The rotor 153 is mechanically connected to be driven by shaft 119 which, as previously explained, is driven from one side of differential 118. The third side of this differential is operated by a vane-device or angle of attack meter 154 through shaft 155. This device is pivoted on the missile externally thereof to be turned by the vertical component of relative wind or angle of attack. As in the case of differential 139, differential 118 algebraically adds the vertical component angles and a to give the resultant angle Shaft 119 turns the rotor 153 in accordance with this resultant angle and the voltage output of angle converter 151 is therefore in accordance with sin 5'. However, the angle of attack in the vertical plane has not only to create a lift in order to compensate for the acceleration due to centrifugal forces, but the lift has also to counteract the acceleration due to gravity. The latter acceleration, of course, depends in part upon the angle of dive. That is, the steeper the dive the less the component to be supported by the wings. However, since the angle of dive varies only between 17 and 45 due to inherent limitations of the radar, while the gravity component varies as the cosine of the dive angle, there is a maximum variation of only 25% in this component. Since the total gravity of 1g is only a small part of the centrifugal acceleration, 25% of 1g is practically negligible for small target distances and the gravity component can thus be assumed constant. Thus compensation can be effected by a constant voltage added to that applied to dividing amplifier 150, as by the secondary 158 of transformer 156 whose primary 157 is energized at constant voltage. Thus the voltage applied to dividing amplifier 150 is proportional to sin E'+k which causes a deflection of fins or vanes 1 and 2 inversely proportional to air density p. While the lift will vary with air speed, the latter does not vary greatly, and since gravity introduces only a relatively small correction it is not necessary to compensate for this second order effect of air speed variation on the lift counteracting the acceleration of gravity.

The operation will, in general, be clear from the foregoing description. Prior to launching from the vertical upright position, the approximate or exact azimuth of the target with respect to the launching station will be known. The gyros are then oriented until the axis 65 of gyro 63 and spin axis 56 of gyro 42 are normal to the vertical target-missile plane. Suitable well-known caging means may be provided whereby the gyro rotors are initially releasably locked with their spin axes in predetermined positions. This position for gyro 42 is as aforesaid while that for gyro 63 will be with its spin axis vertical and parallel with the longitudinal axis of the missile. The electric or pneumatic propelling means for the gyro rotors is energized and switch 88 and potentiometer 106 are set respectively, for the altitude at which the turn into the horizontal path toward the target is to take place and the desired constant-pressure of such path. Since the two will have a relatively small, substantially constant difference, a single set may be used to actuate both.

After the foregoing adjustments have been made and the gyros are up to speed, the latter are released from their caging mechanisms and the rocket propellent is initiated. During the vertical ascent, the gyros maintain their spin axes fixed with respect to external space and, in the manner previously explained, effect pivoting of vanes 1 through 4 in response to any angular deviation of the missile from its vertical path.

As soon as the missile reaches the set altitude or, more exactly, the ambient atmospheric pressure corresponding to the set altitude, switch 88 is closed, motor 82 is energized and rotates at constant speed to pivot potentiometer 77 at a rate substantially that of the desired rate of turn. As soon as turning of potentiometer 77 begins, the control circuits to servomotors 16 and 17 are unbalanced to pivot vanes 1 and 2 counterclockwise, Fig. 2. The missile then responds by turning toward the horizon tal in the vertical target-missile plane and, in so doing tends to restore potentiometer 77 to its null or circuitbalancing position with respect to arm 75. As the action is smooth and continuous, the turn into the horizontal takes place with a substantially constant small displace ment of arm 75 from null position, relatively to winding 77 and at a constant angular rate. When the motor 82 has driven winding 77 through as determined by sliding contacts (not shown) in speed reducer 86, the con tacts separate and open the motor circuit.

At the time of launching the arm of switch is on contact 100a and of switch 103 on contact 1030. These positions are maintained during the horizontal flight. Hence correction of the azimuth of the path of flight can be corrected, in the manner previously described, by radio signals or commands effecting right, left or stop movements of switch 97. Also an altitude is maintained wherein the ambient atmospheric pressure is constant, by means of anemometer 160 operating slider 108a in response to any deviation or change of ambient pressure from that set by adjustment of slider 106 on winding 108.

At the proper instant, based on experience, the practicable range of angle of dive values, speed of target and speed of missile, the control operator effects a signal energizing the radar. Responsively the radar dish is directed upon the target. The signal just mentioned also closes a circuit which energizes and closes clutches 112, 114, and 124. As the radar dish swings about its mutually normal gimbal or pivot axes to direct its axis onto the target in response to the energization of its circuit the shafts 116 and are turned by the angular movement of the dish about its respective axes. Shaft 116 swings the arms of switches 100 and 117 from their central positions. Switch 100, being actuated by movement of the dish about a normally vertical axis, moves onto contact 100b or 100e, depending upon the azimuthal direction of the target relatively to the horizontal path of the missile at the instant the command signal to lock on the target, is given. Thereupon precessing motor 62 is energized from secondary 122 in the proper phase to cause gyroscope 42 to precess in a corresponding direction about axis 50, Fig. 4, and thereby actuate potentiometer arm 59. The resulting pivotal movement of vanes 3 and 4 causes the missile to turn towards the target. It will be understood that the functions just described involve merely the selection of the proper direction of spin of gyro rotor 55 with the circuit hook-up ShDWIl and that the primaries of all transformers may be energized from a common source of AC. At the same time that the arm of switch 100 is activated as just described, the arm of switch 117 is pivoted off its central contact 117a, that is, from the position shown upon Fig. 13. However, as this contact is electrically connected with both arcuate segments, as shown upon Fig. 15, no change is effected at this time by the switch movement, and directional control remains as a constant torque applied to gyro 42 by precessing motor 62.

As the radar dish swings downwardly about its normally horizontal axis, it actuates shaft 125 and thereby the arms of switches 81 and 103. However, no change is effected at this time by the actuation of switch 81 because of its construction identical with switch 117, whereby contact at 81b is maintained. On the other hand, actuation of switch 103 shifts contact from 1030 to 103b, whereby precessing motor 96 is energized from secondmy 126 at constant voltage and slider 75 of potentiometer 77, is adjusted to cause the missile to turn downwardly in the manner already explained. During this time, of course, the gyro 42 remains in control of arms 21, 26, 31 and 37 thereby stabilizing the missile about its longitudinal axis. It will be understood that the response .of the missile to precession of both gyroscopes is substantially instantaneous, so that precession of gyro 42 about axis 50, or of gyro 63 about axis 65 is never more than a few degrees from the normal positions shown upon Figs. 4 and 5.

As the missile path turns toward coincidence with the instantaneous missile-target line, and the radar continues to be directed upon the target, horizontal component of the turn effects rotations of shafts 110 and 115, which are combined in differential 113 and applied to shaft 116, thus moving the arms of switches 100 and 117 back toward, and finally into, their central positions. At this time switch 117 makes contact at 117b and switch 100 at 100d. This makes the control circuit of fins 3 and 4 responsive to angle converter 134 and dividing amplifier 133 and also effects an additional control of the involved circuit through lead 146, potentiometer 147, and slider 148, adjusted by air speed meter 104 whereby the missile is guided in accordance with the equations previously explained.

Likewise the vertical component of angular movement caused by the aforesaid swing toward coincidence results in a reverse turning of shafts 123 and 119, which are combined in differential 121 and the resultant applied to shaft 125. The arms of switches 81 and 103 are thereby restored to central positions wherein switch 81 makes contact at 81a, thereby placing the control of elevons 1 and 2 under control of the dividing amplifier 150, and angle converter 151 as adjusted by the radar 109 and angle of attack meter 154, through differential 118. The same retrograde or return movement of shaft 125, moves switch 103 to make contact at 103a and place precessing motor 96, and thereby gyro 63, under the control of angle resolver 151 and airspeed potentiqmeter 101, according to the equation previously ex plained.

By circuit means not shown, movement of switch 117 to contact 117b effects deenergization of clutches 112 and 114 thereby causes them to open. Likewise movement of switch 81 to contact 81a effects deenerglzatlon of clutches 120 and 124 and causes them to open. There after, control is entirely by the radar, angle of attack meters, angle resolvers, and dividing amplifiers, actlng of course, through precessing torques applied to the gyroscopes. Of course, if desired, the opening of clutches 112 and 114 may be effected by movement of switch 100 to contact 100d and of clutches 120 and 124, by move ment of switch 103 to contact 103a.

It will therefore be seen that I have provided a guided missile which traverses a predetermined trajectory from a vertical path at launching followed by a 90 turn to the horizontal in the general direction of the target.

During horizontal flight the trajectory is at constant preselected atmospheric pressure and is under directional or azimuthal control from the ground. The horizontal path is terminated by the command to lock on the target whereupon the radar effects the necessary angular movements in the vertical and horizontal planes to bring the missile path asymptotically into the instantaneous missile target line. During the entire trajectory, control is directed by the gyroscopes so that flight is steady and stabilized at all times. Thus, at all times direct control is by the gyroscopes while at relatively short range control is effected by the radar through the gyroscopes which at all times retain their stabilizing function.

In each gyroscope, the first axis of freedom is the pivot axis of the outer gimbal, the second axis of freedom is the pivot axis of the inner gimbal, and the third axis of freedom is the spin axis of the rotor. Thus with gyroscope 42, 5' is the first axis, 50 the second axis, and 56 the third axis, while with gyro 63, the first, second and third axes are, respectively, 65, 69 and 74.

The term neutral as applied to the gyroscopes means that each gimbal and the parts supported thereby are balanced so that it has no tendency to rotate about the axis of the gimbal and the center of gravity of the gyroscope is at the concurrence of the three axes.

In the claims and elsewhere, where the expressions responsive to roll or responsive to pitch is used in connection with a gyroscope, the expression is to be taken to mean that roll or pitch, as the case may be, effects a detectable or appreciable angular movement between the casing and spin axis of the gyroscope.

The term dish as used in the specification and claims includes all types of microwave directive arrays capable of directionally projecting a concentrated beam of radia' tion.

While I have disclosed a preferred form of the inven' tion as now known to me, various alterations, modifications and substitutions will occur to those skilled in the art after a study of the foregoing description. Therefore I do not wish to be limited to the precise details of construction shown and wish to have it understood that the disclosure is to be taken in an illustrative rather than a limiting sense; and it is my desire and intention to reserve all those modifications falling within the scope of the subjoined claims.

Having now fully disclosed the invention, what I claim and desire to secure by Letters Patent is:

1. In a self-propelled missile, a casing having a longitudinal axis, first and second control vanes pivoted on respectively opposite sides of said casing on a common axis normal to said longitudinal axis, first and second servomotors in said casing, a driving connection between each servomotor and a respective one of said vanes, first and second neutral universally mounted gyroscopes in said casing, said first gyroscope having its spin axis normal to the longitudinal axis of said casing, said sec ond gyroscope having its spin axis normal to the spin axis of said first gyroscope, means controlling movement of said motors to pivot said vanes in opposite directions in response to relative angular movement of said first gyroscope and casing about said longitudinal axis, and means controlling movement of said motors to pivot said vanes in the same direction in response to relative angular movement of said second gyroscope and casing about an axis parallel to the spin axis of said first gyroscope.

2. In a self-propelled missile, a casing having a longitudinal axis, a pair of control vanes pivoted on respec tively opposite sides of said casing on a common axis transverse to said longitudinal axis, a pair of servomotors carried by said casing, a driving connection between each said servomotor and a respective one of said vanes, a first gimbal journaled in said casing on a first axis parallel to said longitudinal axis, a second gimbal jour naled in said first gimbal on a second axis normal to said first axis, a rotor journaled in said second gimbal for spinning about a third axis normal to said second axis, means responsive to relative angular movement of said casing and first gimbal about said first axis to efiect operation of said servomotors and pivot said vanes in opposite directions about their common axis, and means responsive to relative angular movement of said gimbals about said second axis to effect operation of said servomotors and pivot said vanes in the same direction about their common axis.

3. A guided missile comprising a casing having a longitudinal axis, a pair of control surfaces mounted on said casing for angular movement about an axis normal to said longitudinal axis to control the dihedral angle of said axis with respect to the horizontal plane, servomotor means operable to angularly move said control surfaces, a neutral three-degree-of-freedom gyroscope having a spin axis and first and second gimbal axes normal to each other and to said spin axis, at least one of said gimbal axes being normal to said longitudinal axis means controlled by said gyroscope and responsive to angular movement of said missile about said first gimbal axis to efiect operation of said servomotor means, power means energizable to apply a torque to said gyroscope about said second gimbal axis to cause precession thereof about said first gimbal axis, and means responsive to ambient barometric pressure and energizing said power means in accordance with changes in said pressure.

4. In a self-propelled guided missile, a casing having a longitudinal axis of symmetry, a pair of guide vanes carried at respective opposite sides of said casing for pivotal movement about a common axis normal to said longitudinal axis, first and second servomotors, operating connections between each servomotor and a respective guide vane, a first gimbal pivoted in said casing about a first axis fixed transversely of said longitudinal axis, a second gimbal pivoted on said first gimbal on a second axis normal to said first axis, a gyro rotor journaled in said second gimbal for spinning about a third axis normal to said second axis, said first, second and third axes being concurrent at a point, an arcuate potentiometer winding, means mounting said winding coaxially about said first axis for independent rotation thereabout, a contact fixed to said first gimbal and in sliding electrical contact with said winding, a motor, a driving connection rotating said winding in response to energization of said motor, means responsive to a predetermined ambient atmospheric pressure about said missile to energize said motor, means deenergizing said motor responsive to a predetermined rotation thereof after energization, and circuit means controlling said servomotors and including said potentiometer and contact.

5. A missile as recited in claim 4, and a precessing torque motor having a stator carried by said first gimbal ring coaxial of said second axis, and a rotor fixed to said second gimbal ring, and means for energizing said precessing motor in a predetermined sequence of operations.

6. In a guided missile, a casing having a longitudinal axis, a control vane carried by said casing externally thereof and movable relatively thereto to control angular movement of said missile about a pitch axis fixed transversely of said longitudinal axis, a servomotor carried by said casing, a driving connection between said servomotor and said control vane, a neutral gyroscope carried by said casing and having a first gimbal axis parallel with said pitch axis, a second gimbal axis normal to said first gimbal axis and said longitudinal axis, and a spin axis normal to said second axis, an arcuate potentiometer winding, means mounting said winding coaxial of and for rotational adjustment about said first gimbal axis, a motor, a driving connection between said motor and winding, a slider fixed with said gyroscope about said first gimbal axis and engaging said potentiometer, a control circuit for said servomotor and including said 2O winding and slider, means initiating operation of said motor in response to a predetermined absolute atmospheric pressure ambient of said missile, and means stopping said motor in response to a predetermined rotational adjustment of said winding.

7. In a self-propelled guided missile, a casing having a longitudinal axis, a pair of guide vanes carried at respectively opposite sides of said casing for pivotal movement about a common axis normal to said longitudinal axis, first and second servomotors, a driving connection between each servomotor and a respective guide vane, a first gimbal pivoted in said casing on a first axis normal to said longitudinal axis, a second gimbal pivoted in said first gimbal on a second axis normal to said first axis, a gyro rotor journaled in said second gimbal for spinning about a third axis normal to said second axis, said first, second and third axes, being concurrent at a point, a first potentiometer winding movably mounted in said casing, a slider movable over and in contact with said winding, means so moving said slider in response to and in synchronism with pivoting of said first gimbal, an electric motor, a driving connection between said motor and winding to move the latter, a control circuit for said motor including a switch closed in response to a predetermined decrease in ambient atmospheric pressure, an actuating circuit for said servomotors and including said first potentiometer winding, an electric precessing motor connected with said gimbals and energizable to apply a torque to said second gimbal about the axis thereof, second and third potentiometers, said second potentiometer being manually adjustable, means automatically adjusting said third potentiometer in accordance with ambient atmospheric pressure and a circuit including said precessing motor, switch and second and third potentiometers.

8. In a guided missile, a casing having a longitudinal axis, a control vane carried by said casing externally thereof and movable relatively thereto to control angular movement of said missile about a pitch axis fixed transversely of said longitudinal axis, a servomotor carried by said casing, a driving connection between said servomotor and said control vane, a neutral gyroscope carried by said casing and including a gimbal mount having a first gimbal axis parallel with said pitch axis, a second gimbal axis normal to said first gimbal axis, and a spin axis normal to said second axis, an arcuate potentiometer winding, means mounting said winding coaxial of and for rotational adjustment about said first gimbal axis, a slider contacting said winding and movable in response to relative angular movement between said missile and gyroscope about said first gimbal axis, a motor, a driving connection between said motor and winding, a pressure-responsive switch, a circuit including said switch and motor, means opening said circuit in response to a predetermined angular movement of said winding by said motor, and means controlling operation of said servomotor in response to relative angular adjustment between said winding and slider.

9. A guided missile as recited in claim 8, said pressureresponsive switch closing in response to a predetermined decrease in ambient atmospheric pressure.

10. In a guided, self-propelled missile, a casing having a central longitudinal axis, first and second control vanes pivoted on said casing externally thereof, first and second servomotors, a driving connection between each servomotor and a respective vane, first and second amplifiers, each connected to control a respective servomotor, a first network connected to said first amplifier and including a control potentiometer and a first follow-up potentiometer, in series, a follow-up driving connection between said first servomotor and the slider of said first followup potentiometer, a second network connected to said second amplifier and including a control potentiometer and a second follow-up potentiometer in series, a followup driving connection between said second servomotor and the slider of said second follow-up potentiometer, a

21 yaw potentiometer electrically connected to both said first and second control potentiometers, a roll and yawresponsive gyroscopic means, a first drive actuated by roll from said gyroscopic means to both said control potentiometers, and a second drive actuated by yaw from said gyroscopic means to said yaw potentiometer.

11. A missile as recited in claim 10, the connections of said first network between its control and follow-up potentiometers being reversed with respect to the connections of said second network between its control and follow-up potentiometers, whereby actuation of the slider of said control potentiometers by said gyroscopic means effects pivoting of said vanes in opposite directions and actuation of the slider of said yaw potentiometer by said gyroscopic means efiects pivoting of said vanes in the same direction.

12. A guided missile comprising steering mechanism, a gyroscope, means responsive to relative angular movement between said missile and gyroscope to operate said steering mechanism, a torque motor connected with said gyroscope and energizable to process the same, a radar pivoted on said missile and automatically directed toward a remote target, an angle converter including a fixed coil and a movable coil, said coils being in inductive relation, a driving connection between said radar and said movable coil, a switch, a potentiometer, means adjusting said potentiometer in accordance with the air speed of said missile, and a circuit including said torque motor, switch, potentiometer and movable coil, in series.

13. A guided missile as recited in claim 12, said switch comprising a plurality of fixed contacts and an arm swing- .able to successively engage said fixed contacts, said potentiometer being connected with one fixed contact, two other of said fixed contacts being connected with means for energizing said torque motor in respectively opposite directions, and an operating connection between said radar and the arm of said switch to shift said arm into engagement with said contacts in predetermined sequence.

14. In a guided missile having a longitudinal axis, first and second angle converters, each comprising a fixed coil and a rotatable coil in inductive relation, a radar dish mounted for pivotal movement about mutually normal axes perpendicular to said longitudinal axis, driving means rotating said rotatable coils in synchronism with pivotal movement of said dish about said axes, respectively, means energizing said fixed coils with a voltage inversely proportional to a function of instantaneous range of a target from said missile, two pairs of steering vanes for said missile each pair being pivotable about a common axis, the axes of said pairs being mutually normal and perpendicular to said longitudinal axis, servomotor means each connected to operate a respective vane, and a control circuit for each said servomotor, the circuits of the servomotors controlling one said pair of vanes including one said fixed coil, the circuits of the servomotors controlling the other said pair of vanes including the said other fixed coil.

15. The guided missile of claim 13 each said driving means including a difierential, first and second angle of attack meters carried by and externally of said missile, and an operating connection from each said meter to one side of a respective one of said differentials.

16. In a guided missile, a casing having a longitudinal axis, an angle converter comprising a fixed coil and a rotatable coil in inductive relation, a radar dish mounted upon said casing vfor pivotal movement about an axis normal to said longitudinal axis, means energizing said fixed coil with a voltage inversely proportional to the instantaneous range of a remote target, means connecting said rotatable coil and dish for pivotal movement in synchronism, a steering vane pivotally mounted on said casing, an electric motor for pivoting said vane, first and second potentiometers, a control circuit for said motor and including said rotatable coil and potentiometers, a gyroscope, an operating connection between said 22 gyroscope and the contact arm of said first potentiometer, and a follow-up connection between said motor and the contact arm of said second potentiometer.

17. In a guided missile, a casing having a longitudinal axis, an angle resolver comprising a fixed coil and a rotatable coil in inductive relation, a radar dish mounted upon said casing for pivotal movement about a first axis normal to said longitudinal axis, means energizing said fixed coil with a voltage inversely proportional to instantaneous range of a target, means connecting said rotatable coil and dish for pivotal movement in unison, first and second steering vanes carried by said casing on opposite sides thereof for independent pivotal movement about a common axis parallel to said first axis, first and second servomotors, an operating connection between each servomotor and a respective vane, first and second potentiometers, third and fourth potentiometers, a fifth potentiometer, a control circuit for said first servomotor and including said first, second and fifth potentiometers and said rotatable coil, a control circuit for said second servomotor and including said third, fourth and fifth potentiometers and said rotatable coil, gyroscopic means responsive to angular movement of said" missile about the longitudinal axis of said casing, an operating connection, responsive to said angular movement, between said gyroscopic means and the sliders ofsaid second and fourth potentiometers, said gyroscopic means responsive to another angular movement of said missile about said first axis, an operating connection responsive to said other angular movement between said gyroscopic means and the slider of said fifth potentiometer, and follow-up connections between said servomotors and the sliders of said first and third potentiometers, respectively.

18. A guided missile as in claim 17, a torque motor energizable to eifect precession of said gyroscopic means about said first axis, first, second and third precessing circuits, a switch operable to connect each precessing circuit in sequence with said torque motor, and an operating connection between said radar dish and switch.

19. A guided missile as in claim 18, said first precessing circuit including sixth and seventh potentiometers, said sixth potentiometer being adjustable for altitude, means responsive to ambient atmospheric pressure to adjust said seventh potentiometer, said second precessing circuit including the secondary of a transformer, said third precessing circuit including an eighth potentiometer and said rotatable coil, and means adjusting said eighth potentiometer in accordance with air speed of the missile.

20. A guided missile comprising, in combination, a casing having a longitudinal axis of symmetry, a radar dish mounted for pivoting relatively to said casing about a first axis transverse to said longitudinal axis, power means for pivoting said dish, an angle converter comprising a fixed coil and a rotatable coil in inductive relation, means energizing said fixed coil with a voltage inversely proportional to the range of a remote target, a driving connection between said power means and rotatable coil, first and second rudders pivoted at opposite sides of said casing on a common axis parallel with said first axis, first and second servomotors, a driving connection from each servomotor to a respective rudder, first and second pairs of potentiometers, a yaw potentiometer, a control circuit for said first servomotor and including said first pair of potentiometers, yaw potentiometer, and rotatable coil, a control circuit for said second servomotor and including said second pair of potentiometers, said yaw potentiometer and rotatable coil, each said pair of potentiometers comprising a control potentiometer and a follow-up potentiometer, the potentiometers of said first pair being connected in phase opposition with respect to said second pair, gyroscopic means responsive to roll and ya-w, a connection between said gyroscopic means and the sliders of both control potentiometers, a yaw responsive gyroscope, a connection between said gyroscopic means and said yaw potentiometer, and a 23 driving connection between each servomotor and the slider of its respective potentiometer.

21. A guided missile as recited in claim 20, a motor energizable to apply a precessing torque to said gyroscopic means, and means in circuit with said rotatable coil to energize said precessing torque motor.

22. A guided missile comprising steering mechanism, an angle converter, means to produce an output from said converter equal to sin e/D where e is the angle between the instantaneous missile path and the instantaneous missile-target line and D is the instantaneous missile-target distance, and means responsive to the output of said converter to control said steering mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 2,417,821 Harcum Mar. 25, 1947 2,451,917 Chilowsky Oct. 19, 1948 2,512,693 Sparks et al. June 27, 1950 2,603,434 Merrill July 15, 1952 OTHER REFERENCES Per-ring: German Long-Range Rocket Development," Flight, Nov. 8, 1945, pp. 508, 509, and 511.

White: Guidance for Missiles, Coast Artillery Journal, November-December 1946, pp. 18-22. 

